The present invention is directed to methods of forming a semiconductor device, and, more particularly, to methods of forming a semiconductor device including a diffusion barrier film.
As semiconductor devices become more highly integrated, semiconductor patterns of a semiconductor device (especially width and thickness of interconnections) may decrease. Thus, the electrical resistance value of the interconnections may increase. As the semiconductor industry develops, a faster operation speed of semiconductor devices is in demand. To satisfy such high integration and faster operation speed, the interconnections may be formed of a conductive material of low specific resistance.
Interconnections of the semiconductor device and/or pads electrically connected to the exterior may be mostly made of aluminum. However, as described above, interconnections and/or pads made of copper having a lower specific resistance than aluminum may be used, as higher integration and a faster operation speed is demanded.
However, a number of problems may occur when the interconnections and/or pads are made of copper. For example, copper may be easily oxidized. When a pad is made of copper, a copper oxide layer may be formed on a surface of the pad, which may cause poor contact between the pad and an external terminal (e.g. wire bonding). Accordingly, a copper pattern and an aluminum pattern may be used together in a semiconductor device. For example, lower interconnections may be made of a copper pattern, and final interconnections and pads of the semiconductor device may be made of aluminum patterns. However, problems may also occur in this case. Copper atoms in the copper pattern and aluminum atoms in the aluminum pattern may be mutually diffused to generate a copper-aluminum alloy. The copper-aluminum alloy has a significantly higher specific resistance than copper and/or aluminum individually. Therefore, the electrical characteristics of the semiconductor device may be degraded.